Welcome to the Community, @Papalaura. I'm here to help you make the inactive products active again in QuickBooks Online (QBO).
Reactivating your items is very easy. You'll want to go to your products and services list and do it from there. Here's how:
- Go to the Gear icon, then select Products and Services.
- Click the funnel icon (see the screenshot below for where to find it).
- Select either All (shows both inactive and active items) or Inactive (shows only the inactive items) under Status.
- Hit Apply.

All inactive items have (deleted) tags beside their names. You'll just want to click Make active under the Action column to reactivate them. When you're done, link your purchasing software again.

After setting up everything, I recommend reading these articles to help you manage your sales and customers: Sales and customers articles.
If you want to know what reports to and information on the things that you buy and sell, you can check this article for more details: Use reports to see your sales and inventory status.
Feel free to reply if you have further questions or assistance regarding products and services. Here at the Community, we're always ready to assist you.